I used this to replace my K&N filter element. While the K&N is a reputable brand, I found that the truck was actually sucking the oil off the filter and I had concerns with its ability to keep the incoming air clean under some of the condition the truck experiences.

The 6637 is a serious looking filter, and with the protective prefilter from Riffraff looks impressive under the hood. I'm sure the combination of the prefilter and 6637 will provide plenty of flow and protection for the truck, and outperform the K&N in filtering performance. It fits the K&N intake tube, but I had to pull the K&N air deflector/ baffle from the truck that mounts behind the battery to make room for this filter. Well worth the effort, and another great value product form Riffraff.

Nice filter. Made in USA. Baldwin filter. Good buy.

Riffraff the best by far ,very fast delivery ,and the know their Chit ,everything as expected
Thanks

I bought this and a pre-filter for my 01' cummins for the same price that napa was selling just the filter for. This is a huge improvement over the stock intake box and took a total of maybe 2 minutes to install. The intake hose slid right over the lip of this filter and clamped down snug. For the cummins owners wanting a cold air intake or maybe just a step up from stock, save yourself the money, this does the same thing at a fraction of the price with better filtration than you'd get from an oiled filter

Noticeable improvement from that junk K@N

I like using the 6637. It's much easier to change than factory, and I like knowing it has much more coverage area.

Ahhh air!

Great product and company to deal with.
But usps screwed me. I paid for 2 day shipping, took over a week to get it.

My 7.3 breathes like it should!